This invention relates to means for removing the accumulations of ice that commonly form over the walls and ceilings of railroad tunnels and other unheated underground cavities during prolonged periods of freezing temperatures. It is a common occurrence in railroad tunnels that underground water seeps into the interior of the tunnel through cracks along the walls and ceilings. As long as the temperature in the tunnel remains above freezing, this water runs harmlessly down the walls of the tunnel and either seeps back into the ground through the floor of the tunnel or drains out the ends of the tunnel. However, during those times of the year when the temperature within the tunnel drops below freezing for prolonged periods of time, the water seeping into the tunnel will freeze upon being exposed to the frigid air and form thick accumulations of ice along the ceiling and walls of the tunnel. Unless this ice is periodically removed, it can grow to sufficient dimensions that its weight and internally generated pressures threaten the stability of the tunnel itself. In addition, the accumulated ice may enlarge until it protrudes from the surface of the tunnel a distance sufficient to interfere with the safe passage of trains.
Normally, these accumulations of ice are removed periodically from the ceiling and walls of the tunnel by railroad crews laboriously chipping the ice away with picks or other hand tools. This method of removing the ice is both time consuming and expensive, and requires that the crews work within the tunnel for long hours during those times of the year when the temperature is at its lowest point and when the tunnel itself is least accessible.